Step 1: Prepare the Potatoes

1. Boil the Potatoes: Start by washing the russet potatoes thoroughly. Place them in a large pot, cover with water, and bring to a boil. Cook the potatoes until they are tender, which should take about 20-30 minutes, depending on their size.
2. Peel the Potatoes: Once the potatoes are fully cooked, drain them and let them cool for a few minutes. Peel the skin off while they are still warm, as it will come off easily. Mash the potatoes with a potato masher or pass them through a potato ricer for an even smoother texture.

Step 2: Make the Dough

3. Prepare the Work Surface: On a clean, flat surface (such as a large wooden board or countertop), create a mound with the mashed potatoes. Make a well in the center.
4. Add Flour and Egg: Sprinkle the flour and salt around the potatoes, then crack the egg into the well in the center. Add a pinch of nutmeg (optional) for extra flavor.
5. Mix the Dough: Gently mix the potatoes and flour with your hands, gradually incorporating the flour and egg until a dough starts to form. Avoid overworking the dough to keep the gnocchi light and tender. If the dough feels too sticky, add more flour as needed.

Step 3: Shape the Gnocchi

6. Roll the Dough: Divide the dough into small portions and roll each portion into a long rope about ½ inch in diameter. Use a knife to cut the ropes into 1-inch pieces.
7. Shape the Gnocchi: Use a fork to gently press each piece of dough. Roll each piece along the tines of the fork to create the classic ridged shape, which helps the gnocchi hold onto sauces. You can also use a gnocchi board if you have one, but a fork works just as well.
8. Place on a Tray: Dust a baking sheet or tray with flour and place the shaped gnocchi on it in a single layer. Make sure they aren’t touching, so they don’t stick together.

Step 4: Cook the Gnocchi

9. Boil the Gnocchi: Bring a large pot of salted water to a boil. Gently drop the gnocchi into the water, being careful not to overcrowd the pot. Cook the gnocchi in batches if necessary.
10. Wait for Them to Float: The gnocchi are done when they float to the surface of the water, which usually takes about 2-3 minutes. Use a slotted spoon to remove them from the water and transfer them to a plate.

Step 5: Prepare the Sauce (Optional)

11. Make the Sage Butter: In a large skillet, melt the butter over medium heat. Add the sage leaves and cook for 1-2 minutes, until the butter turns golden and the sage becomes crispy.
12. Toss the Gnocchi: Add the cooked gnocchi to the skillet with the sage butter. Gently toss the gnocchi to coat them in the butter and sage. Cook for another 2-3 minutes to allow the gnocchi to absorb some of the flavor.
13. Serve: Serve the gnocchi with a generous sprinkle of grated Parmesan cheese and freshly cracked black pepper.